<?php

$installer = $this;

$installer->startSetup();
//$installer->addAttribute('order', 'shipping_comment', array('type'=>'tinytext', 'visible' => false, 'default' => ''));
$installer->run("ALTER TABLE `sales_flat_quote_address` ADD `shipping_comment` tinytext  NULL  AFTER `shipping_description` ;");

$installer->endSetup(); 